To stop a ball at waist level, the thigh trap is typically used. The thigh trap involves using the thigh to cushion and control the ball, making it effective for receiving balls that come at or near waist height. However, in some contexts, a player might also use a foot trap or chest trap depending on the specific situation.
In summary, while the thigh trap is the most direct answer, all three types of traps can potentially be used to control a ball at different heights, but the thigh trap is specifically suited for waist level. So, the best answer focusing on waist level would be Thigh trap.